JPH078825Y2 - Gas turbine seal partition structure - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas turbine provided with a space into which cooling air flows between an inner casing for accommodating a turbine portion and an outer casing. The present invention relates to improving the airtightness of a seal partition wall for forming a chamber.

[0002]

2. Description of the Related Art FIG. 6 is a longitudinal sectional view of a main part of a conventional gas turbine. In the figure, 1 is a combustor, and 2 is a turbine rotor in which multi-stage turbine rotor blades 3 are arranged in the axial direction. Turbine vanes 4 are mounted on an inner wall of an inner casing 5 that covers the turbine rotor 2. The outer casing 6 and the inner casing 5 are arranged coaxially, and a high pressure air chamber 7 and a low pressure air chamber 8 divided by a seal partition wall 9 are formed between the both casings. The high-pressure air chamber 7 is filled with high-pressure air from the latter stage of a multi-stage compressor (not shown), while the low-pressure air chamber 8 is supplied with low-pressure air extracted from the middle stage. These air flows from both air chambers through an air passage (not shown) provided in the side wall of the inner casing 5, and the turbine vanes 4
The turbine vanes 4 and the like are cooled by being discharged into the inner casing 5 after passing through inner surfaces such as.

The inside of the inner casing 5 is in a high-temperature and high-pressure state due to the inflow of high-temperature gas indicated by an arrow G. The pressure is highest in the vicinity of the turbine blade 3 in the front stage, and becomes lower in the rear stage. Therefore, by providing air chambers having different pressures according to this pressure difference, it is possible to cool the inner casing 5 with air having the minimum necessary pressure, and suppress unnecessary discharge of high-pressure air. be able to.

Since the seal partition wall 9 is intended to shield the high-pressure air chamber 7 and the low-pressure air chamber 8, it is fixed coaxially to the outer casing 6 and the inner casing 5 maintains airtightness. The sealing member 10 for pressing is not fixed but only pressed. The reason why the inner casing 5 is not fixed is that the inner casing 5 is thermally expanded due to the influence of the high temperature gas G during the operation of the gas turbine and its diameter is increased, or the axial displacement occurs between the outer casing and the inner casing. This is to allow directional relative thermal displacement.

The seal partition wall 9 has a U-shaped support portion 11
Inside, the seal member 10 and the leaf spring 1 divided in the circumferential direction are provided.
2 are housed therein, and as is apparent from the cross section shown in FIG. 7, both ends of the leaf spring 12 integrated with the seal member 10 by the bolt 13 are brought into contact with the inner surface of the support portion 11. The seal member 10 is pressed against the outer peripheral surface of the inner casing 5. Further, the width of the seal member 10 is made slightly smaller than the groove width of the support portion 11 of the seal partition wall, and the high pressure side air is guided to the outer peripheral surface of the seal member 10 to press the seal member 10 against the inner casing 5. The effect to do is further enhanced. As described above, since the seal member 10 is pressed against the inner casing 5 by the leaf spring 12, the seal is maintained even if the inner casing 5 is thermally expanded and its diameter is expanded, or if the inner casing 5 is thermally displaced in the axial direction. Member 1
The airtightness between 0 and the inner casing 5 is maintained, the pressures of the high-pressure and low-pressure air chambers 7 and 8 do not change, and the inner casing 5 is smoothly cooled.

[0006]

In this type of gas turbine, mutual misalignment occurs between the inner casing and the outer casing coaxially arranged due to manufacturing errors, vibration and thermal deformation during operation of the gas turbine, and the like. May occur. However, the above-mentioned conventional structure has a problem that it is difficult to maintain the airtightness of the seal partition wall when the misalignment occurs. This is shown in FIG. FIG. 8 shows a cross section of the seal partition wall, and shows an example in which the seal member 10 divided into four in the circumferential direction is pressed by the four leaf springs 12 with the force F in the central direction. ing. 8A shows the case where the centers of the inner casing 5 and the outer casing 6 are aligned, and FIG. 8B shows the case where the center of the inner casing 5 is decentered downward. As is clear from FIG. 8B, when the inner casing 5 is misaligned, the inner casing 5
And the seal partition wall 9 fixed coaxially to the outer casing 6 widens, so that the upper two seal members 10
The elastic forces of the two leaf springs 12 that press against decrease the elastic forces of the lower two springs. Therefore, the force F by which the upper two seal members 10 are pressed against the inner casing 5 is reduced, and thus the upper two seal members 10 and the inner casing 5 are reduced.
The airtightness between and becomes difficult to maintain.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a seal member fixed to an outer casing and pressed against an inner casing, and a seal partition wall having the pressing means. Is provided on the outer periphery of the seal member to press the seal member against the outer periphery of the inner casing.

[0008]

According to the present invention, since the seal member is pressed by the coil spring formed by connecting both ends and forming an annular shape, the pressing force of the seal member causes the gap between the outer casing and the inner casing as in the conventional leaf spring. Since the seal member is constantly pressed against the inner casing with a constant force, the airtightness of the seal partition wall is maintained even when the inner casing and the outer casing are misaligned.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a main part of a gas turbine according to the present invention, and the same parts as those in FIG. 6 are designated by the same reference numerals. The seal partition wall 9 has the fitting portion 15, the peripheral wall portion 17 and the support portion 11 formed integrally, and is fitted into the fitting groove 16 formed on the inner peripheral surface of the outer casing 6 over the entire circumference. By fitting the joint portion 15, the seal partition wall 9 is supported and fixed coaxially with the outer casing 6. The seal member 10 and the coil spring 14 are housed in the support portion 11, and the seal member 10 is pressed toward the center of the inner casing 5 by the elastic force of the coil spring 14. FIG. 2 is a view of the seal partition wall 9 as viewed from the axial direction, and the annular seal partition wall 9 is divided into upper and lower parts in a horizontal plane, and a flange portion 18 is integrally formed in each of the divided parts. When viewed from the upper half of the seal partition wall, this flange portion is provided at four places on the front and back sides, and bolt holes 32 penetrating the upper and lower flange portions are bored. Further, on the outer periphery of the fitting portion 15, there are four cutouts 1 at the top, bottom, left and right.
9 is provided.

FIG. 3 shows a view of the horizontal joint surface of the seal partition wall 9.
Shown in. The seal partition wall 9 divided into two parts is integrated into the upper and lower parts by inserting the bolts 20 into the bolt holes 32, 32 of the upper and lower flange parts 18, 18 and screwing and tightening a nut (not shown) from below. As a result, an annular seal partition wall 9 is formed.

In the fitting groove 16 provided over the entire circumference of the inner peripheral surface of the outer casing 6, the above-mentioned cutout portions 1 on the upper, lower, left and right sides are provided.
A pin hole and a key portion are provided in the outer casing 6 at a position corresponding to 9. A key 22 is arranged on the upper surface of the lower half side horizontal flange of the outer casing 6 which is divided into upper and lower parts at a position corresponding to the two notch parts 19 in the horizontal direction among the four notch parts 19. The key 22 is fixed to the upper surface of the horizontal flange on the lower half side of the outer casing 6 by screwing the bolt 23 through a bolt hole penetrating the key 22. A groove 21 is provided on the upper half horizontal flange of the outer casing 6 so as not to interfere with the key 22. By fitting the two keys 22 into the left and right cutouts 19, the seal partition wall 9 is vertically positioned with respect to the outer casing 6.
As shown in FIG. 1, on the peripheral wall of the outer casing 6 corresponding to the two notches 19 in one vertical direction, as shown in FIG.
A pin hole 25 is provided. By inserting the pin 24 into the pin hole 25 from the outside, fitting the cutout portion 19 and screwing the bolt 26 into the pin hole 25 to prevent the bolt from coming off, the seal partition wall 9 relative to the outer casing 6 in the left-right direction. Is positioned. The pin 24 is chamfered to have a two-sided width, and is fitted in face contact with the notch 19 of the mating member.

The support member 11 accommodates the seal member 10 and the coil spring 14, and the shape of the seal member 10 is shown in FIG. FIG. 4A shows a cross section,
FIG. 4B is a view of the surface pressed by the inner casing 5. The seal member 10 has a stepped portion 28 for receiving pressure in the longitudinal direction and a groove 27 for reducing the area where the seal member 10 and the outer circumference of the inner casing 5 are in contact with each other to improve the surface pressure.
1 or more are formed, and the lower side in the figure is the high pressure air chamber 7
It is arranged on the support portion 11 so as to be visible. By providing the pressure receiving stepped portion 28, in FIG. 1, the high pressure air is surely guided to the surface of the seal member 10 which faces the high pressure air chamber 7, and the pressure difference between the high and low pressure air chambers causes the seal member 10 to move to the low pressure air chamber. By positively pressing the chamber 8 side, it is intended that high-pressure air is less likely to leak at the seal surface 31 between the seal member 10 and the support portion 11 of the seal partition wall. Further, the seal member 10 is divided into a plurality of pieces in the circumferential direction, and a convex portion 29 and a concave portion 30 are formed at both ends of one portion, and the seal member 10 is formed into an annular shape by combining them. . As shown in FIG. 5, which is a view of the inside of the support portion 11, a coil spring 14 is arranged on the outer peripheral surface of the seal member 10, and both ends thereof are formed in a hook shape so as to lock the both. As a result, the coil spring 14 has an annular shape and presses the seal member 10 toward the center of the inner casing 5 over the entire circumference.

The elastic force of the coil spring 14 causes the seal partition wall 9 fixed to the inner casing 5 and the outer casing 6.
Since the coil spring 14 depends only on the circumferential length of the inner casing 5 wound around the seal member 10 without depending on the relative position of the inner casing 5, the inner casing 5 is misaligned due to vibration during operation of the gas turbine. Even if occurs, the airtightness of the seal partition wall 9 is maintained.

[0014]

As described above, according to the seal partition of the present invention, the elastic force of the coil spring that does not depend on the relative position between the seal partition and the inner casing presses the seal member of the seal partition against the inner casing. Therefore, even if the inner casing is misaligned due to manufacturing error, vibration during operation of the gas turbine, or thermal deformation, the airtightness of the seal partition wall is maintained. Further, compared to the case of pressing the seal member with the conventional leaf spring, since there are many pressing points where the coil spring and the seal member come into contact with each other, the seal member can be pressed with a uniform pressing force over the entire circumference of the seal member. Since it can be pressure-bonded to the inner casing, the airtightness of the seal partition wall is improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a gas turbine according to the present invention.

FIG. 2 is a view of a seal partition wall as viewed from the axial direction.

FIG. 3 is a view of a horizontal joint surface of a seal partition wall.

FIG. 4 is a view showing a shape of a seal member.

FIG. 5 is a view of the inside of a seal partition wall.

FIG. 6 is a vertical cross-sectional view of a main part of a gas turbine according to a conventional example.

FIG. 7 is a view of the inside of a seal partition wall.

FIG. 8 is a cross-sectional view of a seal partition wall.

[Explanation of symbols]

 5 Inner casing 6 Outer casing 9 Seal partition wall 10 Seal member 14 Coil spring

Claims (1)

[Scope of utility model registration request] 1. A seal member fixed to an outer casing and pressed against an inner casing, and a seal partition wall having the pressing means, a coil spring formed into an annular shape by connecting both ends to the outer periphery of the seal member. A seal partition structure for a gas turbine, which is provided.